My above identified patent is directed to a well drilling system which includes a drill cuttings evacuation fluid conduit member or enclosure, sometimes referred to as a "bell nipple", adapted to include an array of fire suppression fluid injector nozzles to minimize ignition of well fluids in an uncontrolled well. The enclosure or well fluids conduit member of the above-referenced patent includes an array of at least three injector nozzles connected to a source of pressure water and/or pressure fire extinguishing material which may be injected into the enclosure to minimize combustion of well fluids which may result from a well which becomes at least temporarily out of control and combustible fluids are allowed to flow and commingle with drill cuttings evacuation fluid being returned from the wellbore. However, in the further development of a suitable system for minimizing the combustion of well fluids or to extinguish combustion of well fluids emanating from a wellbore during drilling operations or the like, it has been determined that certain improvements are desired.
For example, due to the substantial pressure of fluids emanating from an uncontrolled well through the drill cuttings evacuation fluid flowpath, it is desirable to reduce the fluid pressure so that the fire extinguishing fluids may flow freely into and commingle with combustible well fluids to minimize the chance of combustion or to extinguish a flow stream which has already become ignited. Moreover, in accordance with the arrangement in the above-mentioned patent, it is desirable to locate the injector nozzles for the fire extinguishing or suppressing fluids in a position downstream or "above" the location of any branch conduits of the enclosure or bell nipple, such as conduits which allow for fill up of the wellbore, diversion of wellbore fluids and conduits which conduct drill cuttings evacuation fluids away from the well.
Still further, it is desirable to provide a cuttings evacuation fluid enclosure, or so-called bell nipple or "spool", which includes a transverse flange formed at the top end thereof to assist in attaching well control devices if an out of control well condition exists. Moreover, it has been determined that an array of two diametrically opposed fluid injection nozzles is preferable to the provision of additional nozzles in the array so as to provide a more even distribution of flow of fire extinguishing materials through the nozzles and into the space where uncontrolled well fluids are flowing. It is also desirable to provide control valves associated with the fire extinguishment or suppression fluid injector nozzles which provide for positive remote control of flow of fire extinguishment fluids.
It is to the above-mentioned ends, as well as providing other desiderata in fire suppression apparatus for use with drilling hydrocarbon wells, in particular, that the present invention is directed.